I would like to outline some of the motivations and rationale for expanding
ecological studies from a local to regional scale, by interweaving the
history of two field sites and some of the results from these research programs that illustrate the kinds of insights that arise from regional studies with my own observations concerning the growth, acceptance and eventual full embracing of regional studi
es by some segments of the
I'd like to start with a brief synopsis of the recent development of two LTER sites, Harvard Forest, located in central New England and the Luquillo Experimental Forest, in eastern Puerto Rico. Although these sites would seem to share little more than a forested condition and designation as LTER projects their level of commonality is surprisingly high. In 1987 when the HF and LUQ LTER groups were writing their grant proposals, both groups discussed the importance of taking a broad-scale approach to their research by examining the larger regions that their protected sites were embedded in. In the case of LUQ the motivation for scaling up, included the examining processes that were important throughout the tropics, such as deforestation, agriculture and development. In the case of the HF the motivation was primarily based on an interest in understandin g how representative the study area was and to study processes that operated at broad scales. After discussion both groups decided not to pursue these regional-scale studies and to focus attention on the protected and semi-natural forest vegetation that lay within the control of either the US Forest System or Harvard University. This decision wa s based primarily on the reading by the group of the national research community and funding agencies that such broad-scale research would be unfundable. The concerns were two-fold: that working across scales would be difficult to sell, and that scaling- up would necessarily involve studying areas that were heavily impacted by humans. Interestingly, the decision was less determined by the concern over whether we had the tools or information to pursue such studies. In large measure the two research groups believed that we couldn't sell the truly important economic, cultural and environmental issues such as cattle grazing, agriculture and its abandonment and introduced and feral animals anymore than mill towns, agriculture or the growth of suburbia to our reviewers. Consequently, both groups submitted research proposals that emphasized natural processes: wind disturbance, gap dynamics, landslides, fire and avoided mentioning broad-scale research or land- use activity. This last omission was especially interesting b ecause there was ample historical evidence for both study areas that the protected research sites had been completely transformed by prior human impacts.
Chronology of events to follow:
- Upon receiving research funding from NSF both groups immediately started to pursue regional, contextual studies based on the following motivation:
- to place the site in a geographical context
- to ask how representative each site is of the region that it occupies
- to study important ecological processes that operate at a regional scale
- to study important applied issues such as land-use conversion and pollution
The scheme developed at HF looked like this [HF scales] and basically evaluated a variety of processes at the site, landscape, sub-regional and regional scales. At the same time there was a great move in the direction of regional studies in ecology:
Landscape Ecology emerged as an important field with the first Landscape
Meetings at Georgia in 1986 and with NSF began to award grants for studies that focussed on a broad scale and included human as well as natural systems.
- The Bergen Conference on "The Cultural Landscape - Past, Present and Future" in 1986
- The Earth as Transformed by Human Action held at Clark University in Worcester, Massachusetts in 1987
- The 4th Cary Conference on "Humans as Components of Ecosystems" held at the Institute of Ecosystem Studies in 1991
With these kinds of intellectual stimuli that emphasized humans and with
the increasing scientific and policy interest in global phenomena and with the very real political and economic pressure from Congress for scientists and funding agencies to deal with applied issues, ecological science that encouraged broad-scale studies
that extended beyond the bounds of protected individual sites into regional studies that included extensive human-dominated systems became, not just acceptable, but desirable.
Increasingly those of us in LTER projects began to hear how we should be expanding outward until the boundaries of our study regions touched and we came to cover much larger chunks of the U.S.
In 199_, NSF held an Augmentation Competition that sought to increase the funding for LTER sites that would increasingly focus on regional studies and incorporate social sciences and a human dimension into their work.
In 1993 at the All Scientists Meeting in Estes Park there a Workshop of Regionalization that lead to the establishment of a Web Page on Regionalization and also to the eventual symposium on regional studies among LTER sites that was held at the HF in 199
All of this culminated on the LTER side in the development of a call for proposals and eventual funding of 2 new LTER sites that took an urban focus and specifically incorporated these urban areas into their regional setting.
Not surprisingly, both the Harvard Forest and Luquillo LTER sites discovered that a regional perspective that incorporated both natural and human processes has been incredibly important for understanding the ecosystem processes and forest characteristics
at their sites. Both also submitted renewal proposals that emphasized these approaches in 1994.
Provide some examples of the insights that have emerged from these perspectives.
First has to do with vegetation dynamics resulting form a history of land-use activity in the region:
At the scale of a simple forest stand it is now very well confirmed that the following type of dynamic is observable:
Pollen diagram from a forested site in Massachusetts showing 350 years of vegetation dynamics. Basic points [HH pollen]:
- major changes in vegetation through time as a consequence of human activity
- 3 distinct vegetation types
- no analogs through time
- modern vegetation completely distinct from historical
- fine patterning of landscape and differentiation based on specific
However, at a regional scale when we examine the vegetation composition
over time across a fairly modest environmental gradient going from lowland
to upland regions [Cmass area]
We can see that land use was remarkably homogeneous at this scale, at least in terms of the extent of forest cover [Cmass 1830/1985] That pollen [pollen data] sensed from lakes across this regional gradient show a strong tendency to become more similar thru time. Interestingly this begins before European settlement but becomes most accentuated after, thereby showing a decrease in com positional variation The historical distribution of individual tree taxa show a clear pattern of homogenization thru time [Historical data]. Whereas the relationship between climate and tree distribution was strong and statistically significant at the time of European sett lement it is not today. If we look at another regional process we find considerable additional information based on a regional approach. Although the Hubbard Brook and Harvard Forest sites seem adjacent on a U.S. map there has always been a fundamental difference in their interpretation of forest disturbance and dynamics. At the risk of simplification, the HF school has emphasized frequ ent disturbance by major wind storms [hurricane impact], whereas Bormann and Likens have emphasized a steady state or shifting mosaic approach based more on small gaps and infrequent blowdowns. [Forest canopy]. A reconstruction of hurricane impacts for the [NE hurricane] historical period shows, in fact that there is a very strong gradient of hurricane impact across New England an declining from SE to NW. Whereas the Harvard Forest falls within a region that e xperiences >15 windstorms capable of producing large treefall gaps, Hubbard Brook, experienced only 5-6 within the same time period.
When we take a similar approach to Puerto Rico we see a similar strong gradient from E to W across the Island. [PR hurricane] Thus from these studies we have seen, on the one hand that a regional scale shows a tendency over time for a decrease in variation in vegetation and a much finer level of variation in the importance of some disturbance processes then we suspected. Want to close with a reminder of the session later today and with a suggestion to keep our scales of study very open. In this figure of the relationship between forest cover and population thru time we see a very interesting phenomena [Pop/Cover] - alth ough there was a strong inverse relationship between these two factors thru about 1850, from then on the relationship was lost as it first reversed and then broke down all together. The explanation for this is simple. In the Colonial period until the 19t h C., people in the region were living off the agricultural resources of the land. Since the industrial revolution food and most of our resources have come from other parts of the US and globe. Thus although our population and economy are booming we are living off of the food and products from someone else' backyard. In the 18th and 19th C a local to regional scale would have allowed us to understand these dynamics. Currently it is necessary for us to combine both a local, regional and continental or g lobal perspective to truly understand the changes in our land.
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